What the bands are
Bollinger Bands plot a moving average with bands two standard deviations above and below it. Because the width follows recent volatility, the envelope breathes with the market. Price touching a band is not a signal by itself — in a strong trend price rides the band for long stretches. The honest first question is always which regime you are in.
What they can tell you
A squeeze — bands narrowing to their tightest in weeks — says volatility is compressed and a move often follows, though not its direction. A walk along the upper band in an uptrend confirms strength rather than overbought doom. Band midline tags act as dynamic pullback references that many desks watch.
What they cannot tell you
Bands cannot predict direction from a touch, cannot time reversals, and cannot replace a stop. Fading every tag is the classic beginner account killer in trending sessions. Combine with structure and a stop sized from volatility, never from hope.
Where the bands come from
John Bollinger built the tool in the 1980s for a simple reason: fixed-width envelopes are useless when volatility changes. A constant percentage band is too wide in quiet markets and too narrow in wild ones. Scaling the band to a standard deviation makes the envelope adapt. That is the whole idea — the band is a volatility statement, not a prediction engine. The moving average in the middle is typically 20 periods, long enough to smooth noise and short enough to follow the move. Two derived numbers travel with the bands: bandwidth measures how wide the envelope is, and %B says where price sits inside it. Both simply restate the same price and volatility information in a friendlier form.
Common mistakes
The first mistake is treating a band touch as an automatic reversal signal. In a strong trend the touch is the norm, not the exception, and fading it costs real money. The second is confusing a squeeze with a directional call: compression says a move is coming, never which way. The third is mixing timeframes carelessly — a daily squeeze matters more than a five-minute one. Finally, traders forget that the bands are derived entirely from price itself. They add a way of reading volatility, not new information.
How to use them without fooling yourself
Use the squeeze as an alert, not an entry. Use the walk as confirmation you are on the trend side. Write down the rule before the trade, then let the sample decide. For the honest math behind winners and losers, read our glossary pages and the indicators guide.
Download the indicator files — Bollinger Bands Explained
⬇️ Download pipatlas-bollinger-bands.mq4 (MT4 · MIT)
⬇️ Download pipatlas-bollinger-bands.mq5 (MT5 · MIT)
⬇️ Download pipatlas-bollinger-bands.pine (TradingView · MIT)
Install: MT4 / MT5 → File → Open Data Folder → MQL4/MQL5 → Indicators → copy the file in → open MetaEditor and press F7 to compile → drag it onto your chart. TradingView → Pine Editor → paste the file → “Add to chart”. MT4/MT5 already include a built-in Bollinger Bands — this is the editable PipAtlas source version with band-touch arrows and alerts.
Frequently asked questions — Bollinger Bands Explained
Which settings are standard?
A 20-period average with two standard deviations is the tested default. Changing them changes the tool, not the market.
Do bands work on all timeframes?
They measure the same thing everywhere, but higher timeframe squeezes matter more to swing traders.